Mike's PBX Cookbook

SSC Expansion Cabinets

Two types of Small System Expansion Cabinets exist: Fiber and IP. Fiber expansion cabinets are relatively transparent, IP Expansion Cabinets allow for Survivability if communication with the Main cabinet fails (requires an additional keycode).

Fiber Expansion:

The following Fiber Expansion daughterboards, installed on the SSC card in the Main Cabinet, must be paired with the corresponding Fiber Receiver card installed in the Expansion Cabinet (slot 0). Single and dual-port daughterboards may be combined on the SSC.

Expansion DBReceiver CardDistance, Mode
Single-portNTDK22NTDK2310 m (33 ft), Plastic Multimode
NTDK24NTDK253 km (1.8 mi), Multimode
NTDK79NTDK803 km (1.8 mi), Single Mode
Dual-portNTDK84NTDK2310 m (33 ft), Plastic Multimode
NTDK85NTDK253 km (1.8 mi), Multimode

A NTDK23 Receiver Card uses the orange A0632902 Plastic Multimode cable.

Security dongle

NTDK20 SSC cards always require a security dongle, there are two types:

Both devices look identical, but can be identified by the label. The NT_REM must match the main cabinet S/N. A Fiber Receiver card does not require a dongle.

IP Expansion:

The following IP Expansion daughterboards can be installed on the SSC card in both the Main or Expansion Cabinet:

IP expansion SSC cards require a NT_REM dongle. To install, select: "1. Media Gateway/IP Expansion Cabinet" from the "Software Installation Main Menu", and enter the IP address information.

Note: When both Fiber and IP Expansion daughterboards coexist in a system, set the Fiber Expansion daughterboard in Position 1 (Ports 1&3) and the IP Expansion daughterboard in Position 2 (Ports 2&4).

Option 11 Expansion Cabinets
Cabinet / Port:Card Slots:
Main Unit1 - 10
Expansion #111 - 20
Expansion #221 - 30
Expansion #331 - 40
Expansion #441 - 50

Card Slots:

Small system terminal numbers (TN's) comprise Card and Unit numbers.
The cabinet card slot designations are as shown right:

Use commands: STAT CPU and STAT FIL in LD 135 to check the configuration.

NTDK20 DaughterBoard LEDs:

NTDK20 DaughterBoard LEDs
Port Status LED (Layer 7)
Solid Green LEDLink is up and running
Solid Amber LEDLink trying to establish
Solid Red LEDLink is down
LED OffNo DB port present


A survivable IP Expansion Cabinet is able to function without access to the Main SCC, eg, during an outage. This feature is keycode activated. Switchover can be manually invoked with SBFS/SOTS in LD 135, or automatic when the Switchover Time Out timer (SWOTO) expires, set in LD 117. Automatic Switch Back from survival mode is set by the AUTOSB command in LD 117.

Database synchronisation:

The customer database is replicated (during EDD) to the IP Expansion Cabinet SSC's, this is used locally when in Survival mode. A database download can be forced by DWL cab# in LD 43. If a cab# is omitted, the database is sent to all IP cabinets. Any local changes made while is survivable mode will be lost on switch back, as LD 43 and 143 are not available in survival mode.
Dial tone in survival mode is different from that in normal mode. The Flexible Survivable Dial Tone (SURV) is set LD 56.


LD 32:

ENLS xEnable cabinet x
DISS xDisable cabinet x

Disable the cabinet in LD 32, then the fiber port in LD 135.

LD 135:

DIS FIL nDisable fiber optic link n (1-4)
ENL FIL nEnable fiber optic link n (1-4)
LLBK FIL nPerform local loop back test on fiber optic link n
LLBK ip nPerform local loop back test IP connectivity link n
RLBK FIL nPerform remote loop back test on fiber optic link n
SBFS xSwitch Back From Survival. Force IP cabinet to Normal/Slave mode
SOTS xSwitch Over To Survival mode. Force IP cabinet to Local/Survival mode
STAT FILGet status of all fiber optic links
STAT FIL nGet status of fiber optic link or IP link n
STAT IPL cabGet the IP link status between Call Server and MG 1000S
STAT MACGet MAC address of IP daughterboards installed on SSC card
LOCK x IPLock an expansion cabinet (or MG 1000S) in its current operating mode
UNLOCK xUnlock an IP Expansion cabinet (or MG 1000S) from its operating mode

LD 117:

PRT SURV cab#Print Survivability parameters
PRT CAB cab#Print Cabinet parameters
CHG SURV cab# (NO) YESAllow Survivability for each IP Expansion cabinet
CHG AUTOSB cab# (YES) NOAutomatic Switch Back (AUTOSB) option On/Off
CHG SWOTO cab# secondsSwitchover Time Out timer, 2 - (120) - 600 seconds
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